Hemerodromia isochita, Plant, Adrian R., 2015

Plant, Adrian R., 2015, Diversity of Hemerodromia Meigen, 1822 (Diptera: Empididae) in Thailand, the tip of a tropical iceberg?, Zootaxa 4039 (1), pp. 1-56 : 34-35

Hemerodromia isochita sp. nov.

( Figs 51, 52 , 89 )

Diagnosis. Thorax yellow with sharply defined broad blackish median stripe; scutellum and mediotergite blackish; prothoracic ‘collar’ broadly black dorsally. Wing with a short stub of vein CuA2 present; cell bm+dm long, ending distinctly beyond level of R1. Cercus with complex process on inner face with convoluted tip bearing 4 blunt spines largely orientated internally.

Description. Male: Body length 2.0 mm; wing length 1.8 mm. Head. Black, dusted greyish, strongest on upper occiput; antenna and mouthparts yellow, all setae whitish; one pair reclinate ocl; postocular setae uniseriate below, becoming 2–3 serial above where merging with and hardly distinguishable from two pairs small vtl and several fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel 1.8X long as wide, stylus slightly shorter; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Scutum with broad brownish black median stripe, about as wide as prothoracic ‘collar’ anteriorly, becoming broader posteriorly, leaving postpronotal area and lateral margins broadly clear yellow, boundary between dark and yellow pattern quite sharply defined. Prothoracic ‘collar’ broadly on dorsum, scutellum, mediotergite and sometimes dorsal part of anatergite brownish black. Pleura clear yellow (but sometimes with meron and fused anepisternum + katepisternum somewhat dusky); sutures about laterotergite and base of halter blackish. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Yellowish, apical tarsal segment hardly darker. C1 ~ 1.2–1.3X longer than distance between C1 and C2, all setulae minute excepting a few slightly longer apicals. F1 ~ 1.2X long as C1, ~ 4– 5 X long as wide, very slightly constricted 0.2–0.4 from base; femoral formula ~ 7/16–19/16 –20+1–2/7, denticles black, rows converging apically; spines yellow, rather evenly long, not distinctly longer basally. T1 ~ 0.7X long as F1, evenly curved, ventral face shallowly concave; with one row of ~ 15–19 sharply pointed spinose setae ventrally; ventroapical spur very weakly developed; a strong ventroapical apical erect black spinose seta present ~ 3X long as limb is deep apically. Mid and hind legs slender with only small setulae, T3 with a short row of small setae posterodorsally and a ‘comb’ of short setae posteroapically. Wing. Membrane with somewhat dark microtrichia but hyaline basally. Veins brownish yellow to blackish but whitish near base and C yellowish with posterior margin very narrowly dark. Marginal setulae pale yellow. R2+3 evenly curved, joining C ~ 0.6X distance between end of R1 and R4; length of C between ends of R2+3 and R4 quite long, ~1.8X long as R4. R4 slightly S-shaped, angle with R5 at extreme base ~ 80–90°, becoming ~70–80° thereafter, joining C at ~ 90°; R5 ~ 2.2–2.4X long as R4; R4+5 fork distal to M1+2 fork by ~ 0.8–1.0X length of R4; R5 and M1 slightly curved, convergent distally; cell bm+dm long, ending distinctly beyond level of R1. A distinct vestigial ‘stump’ of vein CuA2 present. Halter pale yellowish white. Abdomen. Tergites 1 and 7 yellow, 2–6 and 8 black; sternites yellow; posterior marginal and discal setae small and fine except longer and brownish on tergite 8 posteriorly. Terminalia. Black with dark setae. Cercus elongate, extending as far as tip of epandrium in lateral view with 4–5 strong outstanding spinose setae dorsally on proximal 0.6 and numerous fine longish setae dorsally and on outer face ( Fig. 51 ); slightly in-turned distally with irregularly rounded blunt apex. A complex process situated along inner face of cercus along with convoluted tip bearing 4 blunt spines largely orientated internally ( Fig. 52 ). Epandrium moderately elongate subrectangular with a few distinct setae on outer face and 4–5 narrow elongate processes apically (specialised setae?). Hypandrium rather narrow, largely obscured by epandrium. Female: Similar to male.

Type material. HOLOTYPE ♂, THAILAND: Chiang Mai Province, Doi Phahompok NP, Doi Phaluang, 1,449 m, 20°1.06'N, 99°9.581'E, 14–21.ix.2007, MT, P. Wongchai, [T6164]( QSBG). PARATYPES: 4♂, 1♀, same data as holotype, 7–14.ix.2007, 7–14.x.2007, 28.xi.–5.xii.2007; 1♂, same data as holotype, light trap 13– 14.vii.2007, M. Sharkey & P. Wongprom; 1♂, Chiang Mai Province, Doi Phahompok NP, Kiewlom 1/montane forest, 2,174 m, 20°3.549'N, 99°8.552'E, 28.i.–7.ii.2008, MT, P. Wongchai ( QSBG & NMWC).

Etymology. The specific epithet isochita refers to this species’ similarity to H. chita Smith, 1965 from Nepal.

Remarks. The male terminalia are very similar to H. chita Smith, 1965 from Nepal in both colouration and form of cerci and epandrium. Both H. chita and H. isochita sp. nov. have a distinct ‘stump’ of vein CuA2 present in the wing. Hemerodromia isochita sp. nov. is known only from the mountain Doi Phahompok, Chiang Mai Province, northern Thailand ( Fig. 89 ). All but one of the 8 known specimens were taken in mid-elevation forest (1,449 m) from May to December with one captured in moist hill evergreen forest at 2,200 m in late January.

Figures

FIGURES 51 – 52. Male terminalia of Hemerodromia isochita sp. nov. 51, lateral view of terminalia; 52, Apex of right ‘ complex process’ situated along inner face of cercus. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium.

FIGURES 82 – 90. Distribution of Hemerodromia spp. in Thailand at a resolution of 0.25 ° and symbols sized to 0.5 ° of latitude and longitude. 82, H. demissa sp. nov.; 83, H. epsilutea sp. nov.; 84, H. etalutea sp. nov.; 85, H. flaviventris Yang & Yang; 86, H. furcata Grootaert, Yang & Saigusa; 87; H. fusca Yang & Yang; 88, H. gammalutea sp. nov.; 89, H. isochita sp. nov.; 90, H. namtokhinpoon sp. nov.